Observation of spin-glass behavior in antiperovskite compound Mn_3Cu_(0.7)Ga_(0.3)N

摘要

We present a detailed study of magnetic properties of antiperovsite compound Mn_3Cu_(0.7)Ga_(0.3)N. Ac susceptibility measurements show a peak around "freezing temperature" (T_f), with the peak position shifting as a function of the driving frequency / and magnetic field H. Magnetic relaxation measurements show a slow decay of the remanent magnetization with time below (T_f). These findings consistently demonstrate the existence of spin-glass states in Mn_3Cu_(0.7)Ga_(0.3)N. The behavior may be attributed to either a small amount of disorder, arising from the random occupation of la sites in the space group Pm-3m by mixed Cu/Ga atoms, or the common frustration, or both.